Is confounding by indication selection bias?

Confounding by indication is often confused as a type of selection bias, but it’s actually a type of confounding bias. Confounding isn’t actually a true “bias”, because bias is usually a result of data collection errors or measurement errors.

What is confounding by severity?

Confounding by severity is a type of confounding by indication, where not only the disease but its severity acts as confounder (see Confounding by Indication: An Example of Variation in the Use of Epidemiologic Terminology, Am J Epidemiol.

What is Channelling bias?

Tendency of clinicians to prescribe treatment based on a patient’s prognosis. As a result of the behavior, in observational studies, treated patients are more or less likely to be high-risk patients than untreated patients, leading to biased estimate of treatment effect.

What type of bias is confounding bias?

Confounding bias: A systematic distortion in the measure of association between exposure and the health outcome caused by mixing the effect of the exposure of primary interest with extraneous risk factors.

How do you reduce residual confounding?

Strategies to reduce confounding are:

1. randomization (aim is random distribution of confounders between study groups)
2. restriction (restrict entry to study of individuals with confounding factors – risks bias in itself)
3. matching (of individuals or groups, aim for equal distribution of confounders)

What does indication bias mean?

Strom, the definition for indication bias (also referred as confounding by indication) states that it ‘occurs when the risk of an adverse event is related to the indication for medication use but not the use of the medication itself’ 2.

What type of bias is minimized by blinding?

Why blinding is necessary. Blinding of one or more parties is done to prevent observer bias. This refers to the fact that most (if not all) researchers will have some expectations regarding the effectiveness of an intervention. Blinding of observers provides a strategy to minimize this form of bias.

What is residual confounding bias?

Residual confounding is the distortion that remains after controlling for confounding in the design and/or analysis of a study.

What is residual confounding example?

When you adjust the model relating smoking and Down syndrome for the important covariate of age, then the effect of smoking disappears. But when you make the adjustment using a binary variable (age<35 years, age >=35 years), the protective effect of smoking appears to remain. This is an example of residual confounding.